[PATCH V5 1/1] block: reject I/O for same fd if block size changed
From: Minwoo Im <hidden>
Date: 2021-01-13 14:36:28
Also in:
linux-block, linux-fsdevel
Subsystem:
block layer, filesystems (vfs and infrastructure), the rest · Maintainers:
Jens Axboe, Alexander Viro, Christian Brauner, Linus Torvalds
This patch fixes I/O errors during BLKRRPART ioctl() behavior right after format operation that changed logical block size of the block device with a same file descriptor opened. This issue can be easily reproduced with a single format command in case of NVMe (logical block size 512B to 4096B). nvme format /dev/nvme0n1 --lbaf=1 --force This is because the application, nvme-cli format subcommand issues an admin command followed by BLKRRPART ioctl to re-read partition information without closing the file descriptor. If file descriptor stays opened, __blkdev_get() will not be invoked at all even logical block size has been changed. It will cause I/O errors with invalid Read operations during the BLKRRPART ioctl due to i_blkbits mismatch. The invalid operations in BLKRRPART happens with under-flowed Number of LBA(NLB) values 0xffff(65535) because i_blkbits is still set to 9 even the logical block size has been updated to 4096. The BLKRRPART will lead buffer_head to hold 512B data which is less than the logical lock size of the block device. The root cause, which is because i_blkbits of inode of the block device is not updated, can be solved easily by re-opening file descriptor again from application. But, that's just for application's business and kernel should reject invalid Read operations during the BLKRRPART ioctl. This patch rejects I/O from the path of add_partitions() to avoid issuing invalid Read operations to device. It sets a flag to request_queue in blk_queue_logical_block_size to minimize caller-side updates. Signed-off-by: Minwoo Im <redacted> Reviewed-by: Christoph Hellwig <hch@lst.de> --- block/blk-settings.c | 3 +++ block/partitions/core.c | 12 ++++++++++++ fs/block_dev.c | 8 ++++++++ include/linux/blkdev.h | 1 + 4 files changed, 24 insertions(+)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 43990b1d148b..48a6fc7bb5f5 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c@@ -329,6 +329,9 @@ void blk_queue_logical_block_size(struct request_queue *q, unsigned int size) { struct queue_limits *limits = &q->limits; + if (limits->logical_block_size != size) + blk_queue_flag_set(QUEUE_FLAG_LBSZ_CHANGED, q); + limits->logical_block_size = size; if (limits->physical_block_size < size)
diff --git a/block/partitions/core.c b/block/partitions/core.c
index e7d776db803b..6f175ea18ff3 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c@@ -612,12 +612,24 @@ static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev, int blk_add_partitions(struct gendisk *disk, struct block_device *bdev) { + struct request_queue *q = bdev_get_queue(bdev); struct parsed_partitions *state; int ret = -EAGAIN, p, highest; if (!disk_part_scan_enabled(disk)) return 0; + /* + * Reject to check partition information if block size has been changed + * in the runtime. If block size of a block device has been changed, + * the file descriptor should be opened agian to update the blkbits. + */ + if (test_bit(QUEUE_FLAG_LBSZ_CHANGED, &q->queue_flags)) { + pr_warn("%s: rejecting checking partition. fd should be opened again.\n", + disk->disk_name); + return -EBADFD; + } + state = check_partition(disk, bdev); if (!state) return 0;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 3b8963e228a1..db5b0b75f0be 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c@@ -130,7 +130,15 @@ EXPORT_SYMBOL(truncate_bdev_range); static void set_init_blocksize(struct block_device *bdev) { + struct request_queue *q = bdev_get_queue(bdev); + bdev->bd_inode->i_blkbits = blksize_bits(bdev_logical_block_size(bdev)); + + /* + * Allow I/O commands for this block device. We can say that this + * block device has proper blkbits updated. + */ + blk_queue_flag_clear(QUEUE_FLAG_LBSZ_CHANGED, q); } int set_blocksize(struct block_device *bdev, int size)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 070de09425ad..6d0542434be6 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h@@ -625,6 +625,7 @@ struct request_queue { #define QUEUE_FLAG_RQ_ALLOC_TIME 27 /* record rq->alloc_time_ns */ #define QUEUE_FLAG_HCTX_ACTIVE 28 /* at least one blk-mq hctx is active */ #define QUEUE_FLAG_NOWAIT 29 /* device supports NOWAIT */ +#define QUEUE_FLAG_LBSZ_CHANGED 30 /* logical block size changed */ #define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_SAME_COMP) | \
--
2.17.1
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